JP2003163535A - Two waves shared antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve omnidirectional function of an antenna device excluding interference between antennas, having all in one structure for easy production. <P>SOLUTION: The device is comprised of a monopole antenna 23 which stands on ground 21, and a power supply point 25 is set on the bottom edge of the circumference face. A four-wire helical antenna 27 on the monopole antenna 23 is allocated on the same axis as the monopole antenna 23 via an insulating spacer 26, and the power supply point 28 is set on the top face of the pole. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suitable dual-wave antenna device for selectively receiving either satellite broadcast or terrestrial broadcast provided at the same frequency.

[0002]

2. Description of the Related Art Recently, communication broadcasting services of digital broadcasting using satellite waves of circularly polarized waves of the same frequency and ground waves of linearly polarized waves are being planned. There is an urgent need to develop a horizontal, omnidirectional, two-wave shared antenna device that can be mounted on a satellite for diversity reception.

In FIG. 5, a 4-wire helical antenna 13 is erected on a ground 11 via a spacer 12, and a monopole antenna 14 is erected in parallel with the 4-wire helical antenna 13 at an appropriate interval. 3 illustrates an external configuration in the case of performing.

The 4-wire helical antenna 13 is mounted to receive left-handed circularly polarized waves, has a feeding point 15 at the center of the top of the head, and has a lower end surface (not shown) in contact with the spacer 12 The antenna elements of the set are short-circuited and connected, and the effective antenna length of each set is set to 1λ. On the other hand, the monopole antenna 14 is erected to receive vertically polarized waves and has an antenna length of λ / 4.

When the direction of the monopole antenna 14 with respect to the 4-wire helical antenna 13 is set to 0 °,
The directivity pattern of each antenna 13 and 14 is shown in FIG.
6 (1) shows the H-plane directivity pattern of the 4-wire helical antenna 13, and FIG. 6 (2) shows the H-plane directivity pattern of the monopole antenna 14.

[0006]

As shown in FIGS. 6 (1) and 6 (2), both the 4-wire helical antenna 13 and the monopole antenna 14 cannot obtain omnidirectionality due to mutual interference. In addition, the isolation characteristic cannot be obtained unless the distance between the two antennas 13 and 14 is large, and as a result, the structure has a very large installation area in order to obtain sufficient characteristics. It is not practical as an antenna device of this type that is required to be downsized.

Further, as an integrated structure of these two types of antennas, Japanese Patent No. 3169378 and Japanese Patent Laid-Open No.
No. 001-144531, JP 2001-1968.
There is also a technique described in Japanese Patent Publication No. 23, but for example, one in which a plurality of dipole antennas are arranged in the central axis portion of a helical antenna, one in which a loop or a feeding point is formed in the middle of a pole-shaped antenna, or the like is mounted. Although the structure is complicated and it holds as an idea, it is not practical in terms of manufacturing cost as a product.

The present invention has been made in view of the above circumstances, and an object of the present invention is to eliminate interference between respective antennas while providing a simple integrated structure which is easy to manufacture. An object of the present invention is to provide a dual-wave antenna device that can realize directivity.

[0009]

The invention according to claim 1 is
A monopole antenna erected on the ground and having a feeding point at the lower end of its outer peripheral surface, and two wires having a feeding point arranged coaxially on the monopole antenna via an insulating spacer or It is characterized by being equipped with a 4-wire helical antenna.

With such a structure, it is possible to realize omnidirectionality by eliminating interference between the respective antennas while having a simple integrated structure which is easy to manufacture.

According to a second aspect of the present invention, in the first aspect of the present invention, the monopole antenna and the helical antenna target the same frequency band, and the monopole antenna performs terrestrial broadcasting by linear polarization. The helical antenna is characterized in that it receives satellite waves broadcast by circular polarization.

With such a configuration, in addition to the operation of the invention described in claim 1, diversity reception by terrestrial broadcasting and satellite wave broadcasting becomes possible.

A third aspect of the present invention is characterized in that, in the first aspect of the invention, the helical antenna mounts a load for phase adjustment at a ratio of one line to two lines of the antenna element.

With such a configuration, in addition to the operation of the invention described in claim 1, since the length of the antenna element portion of the helical antenna can be shortened, the overall length of the antenna can be suppressed to be short. It can contribute to further miniaturization.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an external configuration of a dual polarization antenna device according to the same embodiment. FIG. 1 (a) is a perspective view and FIG. 1 (b) is a side view showing the structure of a feed output system. It is a figure. As shown in FIG.
A cylindrical monopole antenna 23 is erected via the. The monopole antenna 23 has a feeding point 25 at a connection point with a feeding member 24 protruding from the ground 21 at the lower end of the outer peripheral surface thereof.

The monopole antenna 23 is configured to receive vertically polarized waves with an antenna length of λ / 4, and an insulating spacer 26 having the same diameter is provided on the upper end surface of the monopole antenna 23. A cylindrical 4-wire helical antenna 27 having the same diameter is also arranged coaxially.

The helical antenna 27 is mounted so as to receive left-handed circularly polarized waves, and a feeding point 28 is arranged at the center of the top of the cylinder, which is the upper end surface, and is in contact with the insulating spacer 26. Two sets of antenna elements are short-circuited at the lower end surface (not shown).

In addition, in this helical antenna 27, 2
One wire for each pair of antenna elements, one for every two wires,
For example, a rectangular phase adjustment load 29 is mounted in the middle of the element line, and the effective antenna length of each set is set to 1λ.

By this phase adjusting load 29, the length of each element line of the two sets of antenna elements can be made uniform, and in each set, only one element line is further below the lower end surface of the helical antenna 27. It is possible to avoid the structure of protruding to the side.

As shown in FIG. 1B, the helical antenna 27 is arranged in the central axis portion up to the feeding point 28 so as to penetrate the insulating spacer 26, the insulating spacer 26, and the monopole antenna 23 together. Power supply and reception output are performed via the semi-rigid cable 30, and this semi-rigid cable 30 penetrates the ground 21 and is led out to the back side thereof.

Similarly, the feeding member 24 of the monopole antenna 23 is also connected to the semi-rigid cable 31 penetrating the ground 21 and led out to the back side of the ground 21 to feed and receive the monopole antenna 23. I will do it.

The ground 21 has LNAs (Low Noise Amp.) For terrestrial waves and satellite waves built therein, and is constructed by directly soldering the semi-rigid cables 30 and 31 to the LNA board.

FIG. 2 shows the directivity patterns of the antennas 27 and 23 in the above-mentioned configuration, when the direction in which the feeding member 24 is provided with respect to the monopole antenna 23 is 0 °.

The data used here is 1 for the ground 21.
The size is [m] × 1 [m], and 2.332 is in the center thereof.
It is a measurement example when the above-mentioned antenna length is realized with [GHz] as the target frequency.

In this case, the helical antenna 27 receives the satellite wave by the left-handed circularly polarized wave, and the monopole antenna 23 receives the ground wave from the base station by the vertically polarized wave. It is an example of measurement assuming.

FIG. 2 (1) shows the H-plane directivity pattern of the helical antenna 27, and FIG. 2 (2) shows the monopole antenna 2.
3 shows an H-plane directivity pattern of No. 3; These Figure 2 (1),
As shown in (2), both the helical antenna 27 and the monopole antenna 23 can obtain substantially satisfactory omnidirectionality.

This is because the helical antenna 27 and the monopole antenna 23 are mutually fed to each feeding point 28, 25.
Although the position farthest away from the antenna, that is, the position where the impedance is high and the characteristic change as the antenna is concerned is close, the insulating spacer 26 having a sufficient height (thickness) is interposed. , It is shown that mutual interference can be avoided by keeping the distances appropriately.

In addition, under the same conditions as in FIG. 2 above, FIG. 3A shows the E-plane directivity pattern of the helical antenna 27 as shown in FIG.
(2) shows the E-plane directivity pattern of the monopole antenna 23.

As shown in FIGS. 3 (1) and 3 (2) in which the upward direction is 0 ° vertically along the antenna axis, the helical antenna 27 has a directivity in an obliquely upward direction with a certain elevation angle. On the other hand, the monopole antenna 23 has directivity to a low elevation angle slightly above the horizontal plane.

As a result, the helical antenna 27 and the monopole antenna 23 have a satellite wave helical antenna 27 having a directivity in the zenith direction at the top even in the directivity pattern in the vertical plane, and have a directivity in the lateral direction. Due to the configuration in which the terrestrial monopole antenna 23 is disposed in the lower part, it can be determined that there is little mutual interference and sufficient isolation characteristics.

FIG. 4 shows the characteristics of the isolation level between the helical antenna 27 for satellite waves and the monopole antenna 23 for terrestrial waves, which is the target frequency band 2.3.
-30 [dB] required near [GHz]
A value of −35 [dB] or less, which is much lower than the value below, is obtained, and it can be seen that isolation is sufficiently achieved between the two antennas 27 and 23.

Therefore, by mounting this antenna device having the structure shown in FIG. 1 on a moving body, diversity reception can be performed by appropriately selecting and receiving one of the satellite wave and the terrestrial wave having a good reception state. Can be realized.

As described above, the antennas 27 and 23 have sufficient characteristics, but by combining these antennas in the vertical direction to form a single pole-shaped structure, the installation area can be made extremely small. Therefore, it can greatly contribute to the miniaturization required as the above-described vehicle-mounted antenna device.

In addition, in the 4-line helical antenna 27,
Since the phase adjusting load 29 is mounted at a ratio of one line to two lines of the element lines of each set and the lengths of the antenna element lines to be paired can be made short, manufacturing on the lower end side of the four-line helical antenna 27. The processing becomes easy, and the length of the antenna as a whole can be kept short, which can contribute to further miniaturization.

Further, each of the monopole antenna 23 and the helical antenna 27 can be realized as a mounting structure in which a conductor is formed on the surface of a dielectric such as FRP by plating, and it is easy to form an integrally molded structure. Therefore, it is suitable for mass production, and the manufacturing cost can be suppressed to an extremely low level.

Further, as described above, the ground 21 is constructed by incorporating LNAs for terrestrial waves and satellite waves in its plate and directly soldering the semi-rigid cables 30, 31 to the LNA board. As a result, the overall configuration of the antenna can be made smaller.

The 4-wire helical antenna 27 has four
Although the present invention has been described as a line, the present invention is not limited to this, and it is needless to say that it may be two lines.
It has been proved by measurement that a sufficient effect is obtained as in the case of the line.

In addition, the present invention is not limited to the above-described embodiment, and various modifications can be carried out without departing from the scope of the invention.

Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, at least one of the problems described in the section of the problem to be solved by the invention can be solved, and it is described in the section of the effect of the invention. When at least one of the effects described above is obtained, a configuration in which this constituent element is deleted can be extracted as an invention.

[0041]

According to the first aspect of the present invention, it is possible to realize omnidirectionality by eliminating interference between the respective antennas while having a simple integrated structure which is easy to manufacture.

According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, diversity reception by terrestrial broadcasting and satellite wave broadcasting becomes possible.

According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, since the length of the antenna element portion of the helical antenna can be made short, the overall length of the antenna can be kept short. And contribute to further miniaturization.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of a dual-wave antenna device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an H-plane directivity pattern of each antenna element according to the same embodiment.

FIG. 3 is a diagram illustrating an E-plane directivity pattern of each antenna element according to the same embodiment.

FIG. 4 is a diagram showing isolation characteristics between the antenna elements according to the same embodiment.

FIG. 5 is a perspective view showing a configuration example of a conventional dual-wave antenna device.

6 is a diagram illustrating an H-plane directivity pattern of each antenna element in FIG. 5;

[Explanation of symbols]

11 ... Grand 12 ... Spacer 13 ... 4-wire helical antenna 14 ... Monopole antenna 15 ... Feeding point 21 ... Grand 22 ... Spacer 23 ... Monopole antenna 24 ... Power supply member 25 ... Feeding point 26 ... Insulating spacer 27 ... Helical antenna 28 ... feeding point 29 ... Phase adjustment load 30, 31 ... Semi-rigid cable

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Moriyoshi Kawasaki             4-17-13 Minamioi, Shinagawa-ku, Tokyo Harada             Industry Co., Ltd. (72) Inventor Ryuichi Hira             4-17-13 Minamioi, Shinagawa-ku, Tokyo Harada             Industry Co., Ltd. F-term (reference) 5J021 AA02 AA13 AB02 AB06 GA07                       GA08 HA06 HA07 JA05 JA06                       JA07                 5J046 AA04 AA07 AB06 AB10 AB12                       UA02

Claims (3)

[Claims] 1. A monopole antenna standing on the ground and having a feeding point at the lower end of its outer peripheral surface, and a monopole antenna coaxially arranged on the monopole antenna with an insulating spacer interposed therebetween. A dual-wave antenna device comprising a two-line or four-line helical antenna arranged. 2. The monopole antenna and the helical antenna target the same frequency band, the monopole antenna receives terrestrial broadcasting by linear polarization, and the helical antenna receives satellite broadcasting by circular polarization. The dual-wave antenna device according to claim 1, wherein 3. The dual-wave antenna apparatus according to claim 1, wherein the helical antenna mounts a load for phase adjustment at a ratio of one line to two lines of the antenna element.